The sequence is defined by a recursion formula. Write the first four terms of the sequence:
a_1=9; a_n=3a_n-1
a_1 = 9
a_2 = 3*9 = 27
and so on
To find the first four terms of the sequence, we can use the recursion formula provided.
Given a starting value of a_1 = 9 and the recursive formula a_n = 3a_{n-1}, we can find each subsequent term by repeatedly applying the formula.
First term: a_1 = 9
Second term: a_2 = 3a_{2-1} = 3a_1 = 3*9 = 27
Third term: a_3 = 3a_{3-1} = 3a_2 = 3*27 = 81
Fourth term: a_4 = 3a_{4-1} = 3a_3 = 3*81 = 243
Therefore, the first four terms of the sequence are 9, 27, 81, and 243.